Car navigation system mounted on the automobile, cell phones, handheld game consoles, PNDs (Personal Navigation Devices) and PDAs (Personal Digital Assistants) have recently been known as the route search apparatus configured to search a route from a place of departure to a destination as described in, for example, JP 2012-141145A and JP 2008-241605A.
For example, the technique disclosed in JP 2012-141145A uses a reference travel time and a variance value representing a variance of the travel time that are set with regard to each link, to search a route from a place of departure to a destination. More specifically, this technique calculates an expected time required for a guide route by sequential summation of the reference travel times of the respective links constituting the guide route, and calculates the probability of the expected time by sequential summation of the variance values of the respective links.